Concrete divider strip



Jan. 30, 1968 D. E; MocK 3,366,022

CONCRETE DIVIDER STRIP Filed NOV. 29, 1965 Fra. 4.

N '\v ATrQQA/EY FH.- f@ v Aww w AWAY @Y United states Patent o 3,366,022 CONCRETE DIVIDER STRIP Donald E. Mock, 527 E. Cypress, Covina, Calif. 91722 Filed Nov. 29, 1965, Ser. No. 510,339 1 Claim. (Cl. 94-22) ABSTRACT F THE DISCLOSURE A concrete divider strip is disclosed which has corrugations extending between its edges. The strip is flexible enough so as to be capable of being unwound from a reel and moved around a roller so that the Strip extends in a horizontal path which is parallel to the axis of the roller in such a mannerV as to be vertically oriented. The strip is rigid enough so as to be capable of being pushed downwardly from such a vertical position into a cement surface.

The art of pouring concrete has rapidly been mechanized over the past decades. This is particularly true in the pouring of large slabs, and especially highway slabs. `Continuous pouring machines pour the concrete, vibrate it, screed it and trowel it so that a continuous ribbon of concrete s formed. Despite the increasing use of continuous concrete pavements which are not divided in any way, there are many locations where transverse or longitudinal divisions of these concrete ribbons are necessary. These primarily comprise those areas which have normal or larger than normal temperature differentials throughout the seasons. Thermal expansion and contraction require such divisions, and if orderly divisions are not made, random cracking occurs. The same is true lwhere the concrete ribbon is laid upon a base which may settle or shift slightly over the life of the pavement. Such shifting would cause cracking, and random cracking causes major diiiculties to the life of the pavement. For these reasons, in most installations, it is desirable to provide for an orderly expansion joint, and a series of uniformly installed stress raisers which cause uniform cracking when cracking occurs. Furthermore, equipment for providing a concrete divider strip to accomplish these aims should desirably be mechanized and should desirably employ an inexpensive, and easy to handle, concrete divider strip.

Accordingly, it is an object of this invention to provide a concrete `divider strip which is economical of construction, and which may be readily employed in dividing a concrete ribbon into separate zones or areas.

It is a further object of this invention to provide a concrete divider strip which may conveniently be coiled to conserve space and ease transportation and handling, and `which may be uncoiled and employed in a concrete ribbon to divide it.

It is a further object of this invention to provide a concrete divider strip which is made of relatively thin polymer composition material and which is corrugated crosswise of the strip so that it may be bent in the plane of lthe strip as well as coiled layer upon layer upon a ree Other objects and advantages of this invention will become apparent from a study of the following portion of this specification, the claim and the attached drawings in which:

FIG. 1 is an isometric view of the preferred embodiment of the concrete divider strip in accordance with this invention;

FIG. 2 is an isometric view of an alternative embodiment thereof;

FIG. 3 is an isometric view of a portion of a freshly laid concrete ribbon showing the concrete divider strip of this invention in place; and

FIG. 4 is an end elevational view of a machine for positioning the concrete divider strip of this inyentlon showing the machine positioning the divider strip 1n a concrete slab taken in section.

As an aid to understanding this invention it can be stated in essentially summary form that it is directed to a concrete divider strip. The concrete divider strip is preferably made of polymer composition material. The divider strip has a relatively long length, and a fixed wrdth. The width is of proper dimension, when considered with the concrete ribbon with which it is to be used, to extend far enough into the ribbon to cause a dividing stress raiser to define where cracks will occur. In general, the width of the strip is between 1A and 1/z the thickness of the slab. The thickness of the strip is suliicient to give it adequate rigidity, when considered in association 4with the material and the corrugation of the strip to thrust the strip edgewise into the still plastic concrete slab. The concrete divider strip of this invention is corrugated, with the corrugations extending at right angles to the length thereof. The corrugations serve two purposes. The iirst purpose is to provide adequate edgewise rigidity for thrusting the strip into the plastic concrete. The second, and more important, purpose is to provide additional flexibility to the divider strip. Normally such :a polymer composition strip is flexible so that it can be normally bent. However, for proper installation of such a strip, it must also be flexible so that it bends about an axis perpendicular to the plane of the strip. Proper corrugations provide adequate flexibility in this direction.

This invention will be understood in greater detail by reference to the following portion of this specification wherein the drawings are described. Referring now to the drawings, the preferred embodiment of the concrete divider strip of this invention is generally indicated at 10. The divider strip 10 has rst and second edges 12 and 14 and is of indenitely long length. Its length is such that it can be conveniently rolled upon reel 16. The strip 10 has corrugations 18 which have their axes extending from one edge to the other and their depth extending in the thickness direction of the strip 10. A particular divider strip 10, which is suitable for use in transverse division of concrete highway slabs, is made of high impact polystyrene, which is a polymer composition material. The particular strip is 2" from edge to edge and is .015" in thickness of the material. The corrugations provide a total thickness of the divider strip of .160. Furthermore, and importantly, the peak to peak distance of the corrugations along the length of the strip is preferably twice the corrugation depth through the strip. Thus, the peak to peak dimension is substantially .320 in the illustrated embodiment.

The particular divider strip illustrated is made by eX- truding a flat strip of the dimensions indicated, and immediately after the extruding die pressing the resulting strip between involute gears of appropriate dimension. This pressing occurs when the extruded polymer composition material is partially set, and when it is in a condition when it is not tacky, but is still hot enough to take a permanent set. An alternative method of forming the corrugated strip is to use a previously formed strip, cut it to appropriate width, heat it and pass it between forming gears when it is in a temperature condition in which it can take a permanent set in accordance with the forming gears.

Referring now to FIG. 3,

illustrated therein are first and second divider strips 10 which divide .a concrete ribbon into slabs 20, 22 and 24. The ribbon was laid between form rails 26 and 28, which are of such construction as to define the width of the ribbon and carry the machinery for laying the ribbon. The spacing of the divider strip s in accordance with the appropriate concrete standards for slab division in the particular circumstances in which the concrete is laid.

Illustrated in FIG. 4 is the mechanized manner in which the strip is inserted into the concrete ribbon. After the concrete laying machinery has passed along form rails 26 and 28, and the finished but still plastic concrete is positioned therebetween, ribbon inserter 30 iS moved along the rails. Ribbon inserter 30 has wheel 32 on rail 26, and a similar wheel on rail 28. Guides 34 and 36 extend across the ribbon inserter 30, and extend across the concrete slab 22 at right angles to the rails. Carriage 38 moves along guides 34 and 36. Reel 16 is rotatably mounted upon carriage 38 and carries strip 10 wound thereon. Such winding conserves space and provides convenient storage and handling.

First guide roller 40 has anges which have a radial e-xtent substantially equal to the width of strip 10. The dis tance between these flanges is sufficient to accept the corrugated strip. The radius upon which the strip is bent around the core roller 40 is great enough to permit such bending in View of the size of the corrugations and ilexibility of the strip 10, in the direction indicated. This bending is in a direction perpendicular to the length and width of the strip. For the dimensions of the strip indicated above, a minimum radius on the core of first guide roller 40 is approximately 21/2 inches, or is slightly greater than the width of the strip. Adjustable strip inserting structure 42 is pivoted upon carriage 38 at 44. Lock bolt 46 locks the strip inserter structure 42 in the desired position. Strip inserter structure 42 carries second guide roller 48 which has a ange width less than the width of divider strip 10. Thus, when the strip 10 is embraced by second guide roller 48, it is supported between the flanges so as to define its widthwise position, but a portion of this strip extends outwardly from the flanges of roller 48. This permits roller 48 to begin the thrust of strip 10 into the plastic concrete slab 22. Inserter roller 50 completes the insertion. Its outer surface is cylindrical and is substantially even with the top of concrete slab 22. Thus, the partially inserted strip from roller 48 is thrust full width down into the plastic concrete. Thus, as the carriage 38 moves from left to right, as is seen in FIG. 4, along its guides the strip 10 is inserted in the concrete. It is clear that the ribbon inserter 30 can be more fully mechanized than is shown. For example, the progress of the carrriage 38 can be powered. Furthermore, a cutoff mechanism for strip 10 can be provided, preferably between rollers 40 and 48 so that the strip is cut off at appropriate lengths so that it reaches from rail 26 to rail 28. While the ribbon inserter 30 is not part of this invention, it should be noted that the guides 34 and 36 are of sucient length so that the inserter roller 50 can move all the way from form rail 26 to form rail 28.

In some cases the paving machine is employe-d for two lanes at a time, and it is desirable to divide the poured strip longitudinally so as to divide it into lanes. It is clear that the divider strip 10 can be employed longitudinally parallel to the form rails and that the basic strip handling equipment of ribbon inserter 30 can be employed simply by orienting the strip handling equipment parallel to the form rails.

It is clear that the concrete divider strip 10 can be employed in alternative embodiments by providing forming rolls in shapes other than the form of involute gears. For example, in the embodiment of FIG. 2, the divider strip 52 has similar characteristics to the divider strip 10. However, the divider strip 52 is formed in between gears which provide a nished strip 52 which has rounded corrugations 54 rather than the corrugations 18 which have substantially planar faces. As is well known in the gearing art, involute teeth provide a structure which resembles a straight sided rackwhile other gear forms are known which provide other shapes. In fact, a conventional, standard gear shape need not be employed but a special gear tooth shape can be provided which produces the desired curved corrugation 54 of divider Strip 52. However, the basic dimensional relationships should be maintained so as. to produce the proper flexibility and rigidity in the various circumstances.

This invention having been described in its preferred embodiment, it is clear that it is susceptible to numerous modifications and changes within the skill of the routine artisan and without the exercise of the inventive faculty. Accordingly, the scope of this invention is define-d by the scope of the following claim.

i I claim:

1. The process of inserting into a concrete surface a flexible, corrugated, polymer composition divider strip in which the corrugations extend transversely between the edges of the strip, unwinding a reel of said strip material from a horizontally movable carriage wherein the axis of the reel extends horizontally in the direction of movement of said carriage, engaging the sides of said strip by means of a flanged guide roller below said reel and on an axis transverse to said reel to turn and bend said strip because of the flexibility of said corrugations to assume a vertically oriented substantially horizontal position over said pavement, and forcing said vertically oriented strip portion edgewise into the surface of the concrete with the corrugations substantially vertical.

References Cited UNITED STATES PATENTS 2,354,586 7/1944 Fischer 94-39 3,194,130 7/1965 Guntert 94-45 3,200,482 8/1965 Brown 94-51 XR 3,269,282 8/1966 Beesley et al 94-39 2,036,379 4/1936 Woodward 94-18 2,039,144 4/1936 Burgess 94-l7 2,168,925 8/1939 Hewes 94-18 2,798,373 7/1957 Harza 94-18 X 2,806,809- 9/1957 Schuh 161-133 X 3,128,576 4/1964 Bradley 94-18 3,265,556 8/1966 Hungerford 161--133 X FOREIGN PATENTS 707,212 5/1941 Germany.

JACOB L. NACKENOFF, Primary Examiner.

n ent requiring correction and that the said Letters Patent shou UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,366,022 January 50, 1968 Donald E. Mock pears in the above numbered pat- It is hereby certified that error ap ld read as corrected below.

In the heading to the printed specification, line 3, for "Donald E. Mock, 527 E. Cypress, Covina, Calif. 91722" read Donald E. Mock, Covina, Calif. assignor to Anjac Plastics, Inc. El Monte, Calif. a corporation of California Signed and sealed this 22nd day of April 1969.

(SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer 

